T-Mobile is looking to SpaceX's satellites in the skies to help flesh out its network coverage. On Thursday, the two companies announced that they will be working together to "bring cellphone connectivity everywhere," including offering "complete coverage in most places in the US." 

The partnership aims to use SpaceX's constellation of low Earth orbit satellites to beam down connectivity that T-Mobile users can tap into. While SpaceX already offers home internet service around the globe through its Starlink program, with this program T-Mobile users should be able to connect to the SpaceX satellites through a "new network, broadcast from Starlink's satellites using T-Mobile's midband spectrum nationwide." 

Although the company hasn't yet offered specifics on where the network will appear, T-Mobile says it should deliver "nearly complete coverage almost anywhere a customer can see the sky," with the companies envisioning this service as a replacement for using satellite phones in remote areas like a national park or in the mountains.

The carrier will start offering service through SpaceX in a beta that will take place in "select areas by the end of next year" as SpaceX launches its Starlink V2 satellites. Once operational, the network should cover the continental US as well as Hawaii, "parts" of Alaska, Puerto Rico and "territorial waters."

The beta will initially be limited just to text messaging (via SMS, MMS and "participating messaging apps") though T-Mobile and SpaceX are open to adding voice and data support in the future (albeit with no timeline given beyond "the coming years"). 

It's not immediately clear if this network will have a special designation on users' devices. The carrier told CNET that the initial launch won't broadcast a 5G signal and that it will share more details "in the future."

Because the new network is broadcasting over T-Mobile's midband spectrum, the wireless carrier said that the "vast majority of smartphones" already on its network will be compatible with the new service and that users won't necessarily need to buy a new phone to tap into the signal. 

The cellular network will be exclusive to T-Mobile customers and will exist alongside SpaceX's Starlink broadband program on future satellites that SpaceX launches. 

"We've always thought differently about what it means to keep customers connected, and that's why we're working with the best to deliver coverage above and beyond anything customers have ever seen before," T-Mobile CEO Mike Sievert said in a statement.

In a tweet, Musk acknowledged that the plan is to add the feature to Tesla cars in the future for emergency texts and calls. Tesla's vehicles have for years relied on AT&T for cellular connectivity, though it remains to be seen if the automaker will switch to T-Mobile in the future. 

T-Mobile and SpaceX aren't partnering on home broadband with this announcement, despite the two offering similar but competing services, particularly for those looking for connectivity in rural areas. For its part, the wireless carrier said it's "always open to ways to further our mission to give more homes reliable broadband" and Sievert noted during the event that he is open to using SpaceX to help provide backhaul for T-Mobile's ground-based cell towers in the future. 

The two companies are touting the program as a global initiative and are extending an "open invitation" to carriers around the world, with T-Mobile promising that it will offer "reciprocal roaming" to other wireless providers who join in. It's unclear if T-Mobile would welcome AT&T or Verizon into this program or if it has an exclusive in the US on its partnership with SpaceX. 

As for pricing, Sievert said the company plans to include it on the carrier's "most popular plans," though older or cheaper plans may need to pay a monthly fee for the feature.

T-Mobile's SpaceX partnership is the latest tie-up between a traditional cellphone carrier and a satellite provider to boost coverage. Last year, Verizon announced it would be working with Amazon's Project Kuiper, a rival to SpaceX and its Starlink program, to augment its 4G LTE and 5G coverage. 

Verizon told CNET that the goal of that partnership -- which isn't exclusive -- was to "make the entire map of the US red," referring to Verizon's brand color and its coverage maps where red indicates areas where you can find its wireless services. However, neither company provided a timeline for when the service would be available, with the Verizon spokesman telling CNET last year that the project was a "few years away." 

AT&T has also been looking at satellites to boost its coverage, including striking a deal last year with satellite company OneWeb to offer connections to the wireless carrier's business users, though it hasn't announced plans for a consumer offering.